Now that the Ninja know Airjitzu, they get briefed about how the next stage to finding the tomb is to get 'The Sword of Sanctuary' from Cloud Kingdom, which can only be reached from the top of the Wailing Alps. The Ninja go on the treacherous mission up the tallest peak in blizzard conditions using their mechs, but Cole struggles with his ghostly form.
As the Destiny's Bounty flies towards the Wailing Alps, Jay, Kai, and Zane practice Airjitzu by attempting to grab a flag atop the ship's mast, while Ronin and Wu watch. The Master of Fire complains that the new armor to their suits is too heavy, but their Master reminds them that they are embedded with Deepstone to keep them from becoming possessed. Jay decides to call Airjitzu "Cyclon-do" and on his next attempt, he reaches the flag and misses, but messes with Ronin by taking his apple.
Meanwhile, Nya, now wearing a ninja suit, finds Cole in his quarters attempting to cope with being a ghost. Nya compares his situation to her becoming the Water Ninja instead of Samurai X, but Cole states he's a ghost now, not a ninja. Nya asks what he can do in this state, but they are interrupted by the Red Ninja, who informs them that Misako is about to brief them on the next clue. Cole thanks Nya for her words and hugs her, noticing his hand briefly turning back to normal.
During the briefing, Jay reveals that he changed Zane's voice to make him sound like a pirate, and while he and Kai share a laugh, Misako says that the second clue is the Sword of Sanctuary, hidden in the Cloud Kingdom. Wu notes that the only way to reach it is through the Blind Man's Eye, which can only be reached by scaling Ninjago's tallest mountain—the Wailing Alps.
As the Bounty reaches the mountain, the ninja suit up in their respective mechs; Kai in the Fire Mech, Jay in the ElectroMech, Cole in his Earth Mech, and Zane in his new Ice Mech. Cole questions whether he should come, given that he is a ghost, and that he hadn't practiced Airjitzu, but the other ninja and Nya convince him otherwise, and they are deployed. As the others land, Cole lands face first since he could hardly control his mech, but the others tell him despite what they are, they're brothers above all, and they'll pick him up so he'll return the favor. With this, they begin climbing up the mountain.
Back on the Bounty, Nya reports that the Blind Man's Eye is only four hours away. Ronin questions the name of the Wailing Alps, and Misako explains of the natural phenomenon in which sudden large wind gusts have been known to blow climbers off the side of the mountain.
On the way up, Jay and Kai discuss the power and importance of the Sword of Sanctuary: after a while, Kai asks Zane how much further they have to go which he replies is at least 100,000 steps. Jay, who is counting each step, soon notices a Walloper and calls it a goat. Kai points out they've ridden them before, but confuses it for a yak, while Jay changes his opinion and calls it a cow. Zane and P.I.X.A.L. notice fresh tracks and realize Morro is far ahead. A wind gust soon blows through but leaves them unable to stay put even if they anchor down. Cole nearly falls over the edge but is saved by Zane.
As the ninja continue, the Ghost Warriors observing from a higher ledge in the Mech-enstein, are told by Soul Archer they'd never catch up. Bansha notices Morro is struggling, Lloyd now becoming stronger and fighting his possession. Bansha states that since he lost the Allied Armor of Azure, they can't lose the Sword of Sanctuary, while Soul Archer tells him to abandon Lloyd. Morro points out the Sword and getting into the Tomb would be pointless without a Spinjitzu master, and they follow his orders. Bansha offers to at least slow down the ninja, screaming and sending an avalanche towards them. This causes them to lose control of their mech and results in the Fire, Earth, and Electro mechs being destroyed. Just before the Ice Mech goes over a cliff with Zane, Kai, and Jay on it, Cole, having created a body made of snow, saves them at the last minute. Wanting to test out his new abilities farther, he possesses the Ice Mech and makes up the lost ground and goes further, causing Kai to remark he gave the mech "Boo-sters."
In the Bounty, Ronin is amazed they're going so fast, to which Nya stated Cole found his second wind. Ronin, however, stated they're cutting it close, as the Blind Man's Eye will be there soon.
Upon reaching the Hanging Temple, the Ghost Warriors soon notice the ninja are still coming, resulting in Morro deciding to reach the summit on his own, while they take care of the ninja, despite Soul Archer's warning about the wind, to which Morro states that he controls the wind.
The ninja are close to the Hanging Temple when Soul Archer lands a hit on Kai. Everyone expects him to turn into a ghost, though then realize that the Deepstone did prevent him from transforming into a ghost. Using Mech-Enstein, they are brought onto the temple and fight Bansha while Zane and Ghoultar battle in their mechs. Another gust soon comes down and nearly blows Kai, Jay, and Cole off the Temple, while near the summit, Morro yells out he controls the wind and yells for it to stop, which it does.
Zane soon gets the Ice Mech back on solid ground and commences his fight against Ghoultar while Jay knocks Soul Archer off the roof, though he loses his aeroblade in the process. As the ninja head-on, Zane attaches his mech to Mech-Enstein, ejects himself, and sends both mechs and Ghoultar down the mountain in a giant snowball. Soul Archer attempts to stop the ninja, though misses resulting in his arrow turning a bridge intangible.
The ninja come close to catching Morro, but struggle to get a grip on the icicles, though it helps Jay reclaim his aeroblade. The Blind Man's Eye soon approaches, and the ninja realize there's only one way to reach it in time—Airjitzu. Cole is hesitant since he never practiced, but everyone tells him they'll catch him. Kai jumps and does Airjitzu, successfully reaching the top. Zane and Jay follow suit, but Cole still thinks he'll blow off the mountain and die, but Kai tells him that since he's a ghost, he can't die. With this in mind, Cole performs Airjitzu and lands, just as the Blind Man's Eye begins to pass. All four ninja soon perform Airjitzu and reach the storm, leaving Morro behind. Soul Archer sees he missed the window while Bansha states there will be other chances, and notices Ghoultar is nowhere to be found.
In the Bounty, Nya notices the ninja's beacons disappear, while Master Wu informs her they're in the Cloud Kingdom now. Just then, Ghoultar crashes below them and is captured by Ronin in a deepstone cage. As he and Master Wu bring him up for questioning, Nya wonders what state the ninja are in now. They soon wake up outside of the Cloud Kingdom and begin approaching it, determined to find the Sword of Sanctuary.
- Bansha - Kathleen Barr
- Cole - Kirby Morrow
- Ghoultar - Paul Dobson
- Jay - Michael Adamthwaite
- Kai - Vincent Tong
- Misako - Kathleen Barr
- Morro - Andrew Francis
- Nya - Kelly Metzger
- P.I.X.A.L. - Jennifer Hayward
- Ronin - Brian Dobson
- Soul Archer - Brian Dobson
- Wu - Paul Dobson
- Zane - Brent Miller
- The Preeminent (mentioned)
- Allied Armor of Azure (mentioned; error)
- Sword of Fire (mentioned)
- Sword of Invincibility (mentioned)
- Sword of Invisibility (mentioned)
- Sword of Destiny (mentioned)
- Sword of Sanctuary (pictured)
- Samurai Mech/Mech-enstein (Samurai Mech; mentioned)
- Destiny's Bounty
- Earth Mech
- Fire Mech
- Ice Mech
For the transcript of the episode, click here.
- Zane mentions numerous different unknown swords, one being the Sword of Destiny.
- The title is a pun on the phrase, "peek-a-boo."
- The parka hood piece that Kai, Jay, and Zane wear was originally primarily used by Arctic explorers in the LEGO City Arctic sets.
- The "Don't have a cow" gag from The Simpsons is referenced in the walloper scene: Jay calls the walloper a cow, Kai says his version of Bart's line i.e, "I'm about to have a cow."
- According to Zane, the Wailing Alps are at least 3 leagues and 28 fathoms. This rounds up to about 54,850 feet above sea level.
- This is nearly twice the height of Mount Everest, the tallest mountain on Earth.
- This marks the first episode where the ninja gain their Deepstone armor except Cole and Lloyd.
- This is the first episode where all of the ninja's mechs except Lloyd's were featured not only in the same episode but also in the same scene. Kai's Fire Mech, Cole's Earth Mech, Jay's ElectroMech, and Zane's Ice Mech all appear as they climb the Wailing Alps. Nya's Samurai Mech also appears, but only in its transformed Ghost mech form.
- This is also the first appearance of Kai's Fire Mech since "Rise of the Spinjitzu Master," in which it was abandoned on the Island of Darkness, as well as the first appearance of Cole's Earth Mech since "The Titanium Ninja." Both were the final episodes of their respective seasons.
- This is the Ice Mech's first appearance. While no background is given on the mech in this episode, the Ninjago website would later explain that it was built by Nya.
- This episode continues with the subplot set up in "Stiix and Stones", regarding Zane's damaged voice. In this episode, Jay programmed a pirate voice into Zane, just for his amusement.
- Nya stated in "Weapons of Destiny", one of the first episodes in the series, that her favorite color was blue. In this episode, she responds "It's my favorite color" when Kai tells her that the color of her gi suits her well. However, it is unclear whether she was referring to the partial blue coloring or the main maroon coloring, though she was looking at her maroon sleeve when she said it.
- Because the ninja wear parka hoods for most of the episode, this is the first and only episode to show Zane's entire face when he has his blue eye visor on. The only other times it can be seen are when he's wearing his ninja mask, which covers up the bottom half of his face.
- Cole is the only one of the original four ninja who did not wear a parka hood, due to being a ghost. This is because the wind doesn't affect ghosts, as stated by Soul Archer. This is similar to when Zane doesn't need a spacesuit, due to being a Nindroid, in "The Void."
- This is similar to how Zane wears a breathing device for his Scuba suit in Seabound despite not needing to breathe air. As explained in "Long Live the King," he wears it because he likes how it completes his attire. This may also be the reason he wears a parka in this episode.
- When asked how Cole's hand was able to become solid, as seen when he hugged Nya and when he held onto his mech, Tommy Andreasen responded, "Poor judgement during production. I hate it."
- This is the first episode that ends with the original ninja awakening in another realm, followed by "Big Trouble, Little Ninjago."
- When Morro tries to control a gust of wind and later watches the ninja ascend into the Blind Man's Eye, he is wearing the Allied Armor of Azure, despite it being destroyed in the previous episode.
- When Bansha and Soul Archer observe that Morro didn't make it, Bansha says Soul Archer's line and vice versa.
- For a split second in the avalanche scene, Cole is wearing Deepstone shoulder pads, despite never receiving any due to being turned into a ghost.
- When Cole possesses Zane's mech, his appearance on the mech's screen is mirrored.
- Despite the Soul Archer saying that the wind doesn’t affect ghosts, Cole was affected.
- It's unknown why Zane wore a parka hood in the first place, since he's a robot and theorically shouldn't feel cold.
- Cole says "I hate heights," even though he has been seen climbing a mountain in Ninjago before in "The Golden Weapon."
- When Ghoultar shakes the Cole, Kai, and Jay off the Ice Mech, Cole goes into a pile of snow, and when he gets out of the snow there is an indent, which isn't possible since he's a ghost.
- When Nya checks in on Cole at the beginning of the episode, her armor pads briefly disappear.
For the gallery of the episode, click here.